Epilepsy affects 1-2% of the population. Half of all new cases arise in infancy through early adolescence. Seizure outcomes are highly varied. Epilepsy can be a life-long intractable disorder or may resolve after only a few seizures. Many individuals, however, follow a repeated remitting-relapsing course for the first several years before attaining lasting remission. Two issues relevant to evaluation, treatment, management, counseling, intervention, and potentially prevention are poorly understood: 1) More than half the adults with intractable epilepsy who are treated surgically have epilepsy of childhood onset, yet, prospective studies find few children with surgically treatable intractable epilepsy. 2) In otherwise neurologically normal adults with childhood onset epilepsy, many of whom are in remission and off medication;educational and social outcomes are impaired relative to non-epilepsy controls. Explanations for both observations are not evident in the extant literature. Firstly, data come from retrospective analyses of refractory patients only. Few data exist from children followed from onset to surgery in adulthood. Secondly, studies reporting long-term social and educational outcomes characterize only final seizure outcomes after many years thus ignoring an often complex remitting-relapsing process that evolves over >10 years as well as behavioral and psychiatric co- morbidity present from an early age, even predating the seizures. The Connecticut study is an ongoing prospective cohort of 613 children (initially 1 mo - 15 yr) recruited when first diagnosed with epilepsy (1993- 7, median follow-up ~10 years). As the cohort matures into late adolescence/early adulthood, we will pursue two lines of investigation: 1) Presence and progression of hippocampal disease, its frequency and factors that identify patients with focal epilepsy most likely to develop it;2) Correlation of seizure outcomes with psychiatric, behavioral, social, educational, and health-related quality of life outcomes, and an assessment of the extent to which psychiatric and behavioral conditions, independent of seizure variables, explain social and educational outcomes. The Connecticut study is uniquely suited to address these questions concerning the consequences of childhood onset epilepsy in young adults. The examination of hippocampal volumetry, changes in volume and T2 relaxometry will provide the first prospective information about the natural history, determinates, and early detection of the most common form of surgically treated epilepsy.